Low noise ejector for a turbomachine

ABSTRACT

A turbomachine includes a compressor and an ejector. The ejector includes at least one nozzle having a first end portion that extends to a second end portion defining a flow region. The second end portion includes a variable outlet for controlling an airflow from the compressor.

BACKGROUND OF THE INVENTION

The present invention relates to the art of ejectors and, more particularly, to a low noise ejector for a turbomachine.

At least some known ejectors mix two flow streams, a high-pressure primary or motive stream and a low-pressure secondary or suction stream, to produce a discharge flow with pressure intermediate to or lower than the two input flows. The ejector nozzle facilitates this mixing process by accelerating the high-pressure motive flow creating a high speed jet. The high speed jet is channeled through a mixing tube or chamber to entrain the low-pressure suction flow. The two mixed flows are then discharged, typically through a diffuser.

The motive flow is throttled to match ejector output to a turbine operating at off-design load and/or ambient conditions. Existing throttling devices maintain a constant high speed jet diameter as output is reduced. In such devices, flow is reduced by lowering an effective velocity of the motive flow. Reducing velocity of the motive flow in a throttled condition inhibits entrainment of the ejector and thus limits an overall throttling range and degrades entrainment performance.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with one exemplary embodiment of the invention a turbomachine includes a compressor and an ejector. The ejector includes at least one nozzle having a first end portion that extends to a second end portion defining a flow region. The second end portion includes a variable outlet for controlling an airflow from the compressor.

In accordance with another exemplary embodiment of the invention, an ejector for a turbomachine includes at least one nozzle having a first end portion that extends to a second end portion defining a flow region. The second end portion includes a variable outlet configured to controlling an airflow from a compressor.

In accordance with yet another exemplarily embodiment of the invention, a method of controlling an airflow through an ejector for a turbomachine includes generating an airflow in a compressor portion of the turbomachine, guiding the airflow to an ejector, passing the airflow to a nozzle of the ejector, and passing the airflow through a variable outlet portion of the nozzle.

Additional features and advantages are realized through the techniques of exemplary embodiments of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with advantages and features thereof, refer to the description and to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a gas turbine engine having a low noise ejector including a nozzle having a selectively variable orifice in accordance with an exemplary embodiment of the invention;

FIG. 2 is a partial schematic representation of a nozzle having a selectively variable orifice in accordance with an exemplary embodiment of the invention illustrating the selectively variable orifice in a first configuration;

FIG. 3 is a partial schematic representation of the nozzle of FIG. 2 illustrating the selectively variable orifice in a second configuration;

FIG. 4 is a partial schematic representation of a nozzle having a selectively variable orifice in accordance with another exemplary embodiment of the invention illustrating the selectively variable orifice in a first configuration; and

FIG. 5 is a partial schematic representation of the nozzle of FIG. 4 illustrating the selectively variable orifice in a second configuration.

DETAILED DESCRIPTION OF THE INVENTION

With initial reference to FIG. 1, a turbomachine, shown in the form of a gas turbine engine constructed in accordance with an exemplary embodiment of the invention, is indicated generally at 2. Turbine engine 2 includes a compressor 4 having a plurality of compressor stages, four of which are indicated at 6 through 9. Compressor 4 is operatively connected to a turbine 12 via a shaft 14. Turbine 12 includes a plurality of turbine stages, three of which are indicated at 17 through 19. Turbine 2 also includes a cooling system 30 that directs a cooling airflow from compressor 4 to turbine 12. That is, cooling air is extracted from various ones of stages 6 through 9 and passed to corresponding ones of stages 17 through 19 of turbine 12.

Towards that end, cooling system 30 includes a first cooling circuit 40 that interconnects compressor stage 7 with turbine stage 19. In the embodiment shown, compressor stage 7 is a mid-pressure stage that is connected to a corresponding mid-pressure stage 19 of turbine 12. Cooling system 30 also includes a second cooling circuit 44 that interconnects compressor stage 8 with turbine stage 18. Compressor stage 8 is at a higher pressure than stage 7 and thus in connected to stage 18, which, likewise, is at a pressure higher than stage 17. In addition, cooling system 30 is shown to include a bypass circuit 47 having a bypass valve 48 that is selectively operated to maintain internal pressure within turbine engine 2.

In order to utilize as little high-pressure air from compressor 4 as possible, second cooling circuit 44 is provided with an ejector 55 that is operatively connected to first cooling circuit 40 via a connector circuit 58. With this arrangement, a high pressure primary or motive airflow passing through ejector 55 draws in a portion of a lower pressure secondary or suction airflow from first cooling circuit 58. The high-pressure airflow and low-pressure airflow mix to form a combined airflow that is directed through a primary or motive nozzle 60 located within ejector 55. Motive nozzle 60 accelerates the high pressure fluid to a higher speed to substantially match a pressure and speed of fluid within, for example, turbine stage 18. However, as pressure within turbine stage 18 varies over an operating range of turbine 12, ejector 55, as will be discussed more fully below, is selectively adjustable in order to control pressures within second cooling circuit 44 to match pressures within turbine stage 18 over a wide operating range of turbine 12.

Reference will now be made to FIGS. 2 and 3 in describing motive nozzle 60 constructed in accordance with a first exemplary embodiment of the invention. As shown, motive nozzle 60 includes a first end portion 70 that extends to a second end portion 71 through an intermediate portion 72 defining a flow region 75. As will be discussed more fully below, second end portion 71 includes a variable outlet 78. In accordance with the exemplary embodiment, variable outlet 78 is defined, in part, by a chevron 79 arranged at second end portion 71. Chevron 79 is designed to lower an overall noise output from ejector 55. Chevron 79 is configured to extend towards a centerline (not separately labeled) of ejector 55 in order to control airflow. Chevron 79 defines a first dimension 85 for variable outlet 78.

In further accordance with the exemplary embodiment shown, ejector 55 includes a secondary motive nozzle 88 arranged within motive nozzle 60. Secondary motive nozzle 88 is operatively connected to an actuator shaft 91 through a plurality of struts, one of which is indicated at 93. As will be discussed more fully below, actuator shaft 91 is selectively operated in order to shift secondary motive nozzle 88 within flow region 75 in order to control an overall output from ejector 55. Towards that end, secondary nozzle 88 includes a first end portion 97 that extends to a second end portion 98 through an intermediate portion 99. Intermediate portion 99 defines a secondary chevron 104 that correspondingly defines a second dimension for variable outlet 78.

With this arrangement, during base load operation of turbine 2, secondary motive nozzle 88 is shifted to a first configuration as indicated in FIG. 2 wherein air passing through flow region 75 passes through variable outlet 78 configured at first dimension 85. However, during off baseload operation or, when ambient air temperatures are outside of design parameters, secondary motive nozzle 88 is shifted towards a second configuration as indicated in FIG. 3 where the airflow flowing through flow region 75 is guided through variable outlet 78 configured at the second dimension 107. More specifically, in the second configuration illustrated in FIG. 3, secondary chevron 104 abuts chevron 79 closing or narrowing variable outlet 78. Of course, depending on the particular operating speed and/or, ambient air conditions, secondary motive nozzle 88 can be shifted to any one of a plurality of intermediate positions (not shown) in order to establish any number of intermediate dimensions for variable outlet 78 to produce a desired airflow pressure/speed to provide cooling air to turbine stage 18. With this arrangement, ejector 55 is selectively configurable to produce a wide range of pressures/volumes so as to match operating pressures within a turbine stage across a broad operating range of turbine 2.

Reference will now be made to FIGS. 4 and 5 in describing a motive nozzle 120 constructed in accordance with another exemplary embodiment of the invention. As shown, nozzle 120 includes a motive pipe 124 having a first end portion 128 that extends to a second end portion 129 through an intermediate portion 130 so as to define a flow region 132. In a manner similar to that described above second end portion 129 includes a variable outlet 132. Nozzle 120 further includes a plurality of chevrons, one of which is indicated at 136 which, as will be discussed more fully below, define an outlet geometry or dimension for variable outlet 132. In a manner also similar to that described above, chevrons 136 extend towards a centerline (not separately labeled) of ejector 55 so as to minimize noise output during turbine operation. In the embodiment shown, each chevron 136 includes a first end section 138 that extends to a second end section 139 through an intermediate section 140. In accordance with the exemplary embodiment shown, each chevron 136 is pivotally mounted to motive pipe 124 and thus includes a hinge 142. As will be discussed more fully below, chevrons 136 are selectively pivotable between a first position, illustrated in FIG. 4 and a second position, indicated in FIG. 5.

In order to control the selective movement of chevrons 136, nozzle 120 is provided with a chevron collar 154 that is slidingly mounted to motive pipe 124. Chevron collar 154 includes a first end 157 that extends to a second end 158. Second end 158 is operatively connected to first end section 138 of the plurality of chevrons 136. First end section 157 is operatively connected to an actuator rod 161 that is selectively shiftable in order to move or position chevrons 136 between the first position illustrated in FIG. 4 and the second position illustrated in FIG. 5.

During normal or baseload operation of turbine 2, actuator rod 161 is shifted so as to cause chevron collar 154 to move chevrons 136 to the first configuration illustrated in FIG. 4 establishing an outlet portion or orifice 165 having a first dimension 166. In this manner, a sufficient airflow passes through flow region 132 into compressor stage 18. During off base load operations or, when ambient temperatures are outside design parameters, actuator rod 161 acts against chevron collar 154 to close chevrons 136 shifting orifice 165 to a second dimension 169 that is smaller than first dimension 166. In this manner, cooling air at a sufficient volume and a sufficient temperature is passed to turbine stage 18 in order to accommodate off base load operation.

At this point, it should be appreciated that ejector 55 in accordance with provides a selectively variable airflow output thus enabling cooling circuit flow to be tailored to pressure conditions within turbine section of a turbine engine across wide operating ranges. That is, the ejector, in accordance with the exemplary embodiment of the invention, is more tunable across a broader range or operating conditions so as to provide more control at hotter temperatures and additional adjustments to provide cooling air across a wider operating range. It should also be understood that the variable outlet can be formed using a variety of different structures.

In general, this written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of exemplary embodiments of the present invention if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

1. A turbomachine comprising: a compressor; and an ejector fluidly connected to the compressor, the ejector including at least one nozzle having a first end portion that extends to a second end portion defining a flow region, the second end portion including a variable outlet for controlling an airflow from the compressor.
 2. The turbomachine according to claim 1, wherein the at least one nozzle includes a first nozzle and a second nozzle, the second nozzle being slidingly disposed with the first nozzle.
 3. The turbomachine according to claim 2, wherein the first nozzle includes a first chevron portion that defines a first dimension for the variable outlet and the second nozzle includes a second chevron portion that defines a second dimension for the variable outlet, the second dimension being distinct from the first dimension, the second nozzle being shiftable between a first position, wherein airflow from the compressor passes through the variable outlet configured at the first dimension, to a second position, wherein the airflow from the compressor passes through the variable outlet configured at the second dimension.
 4. The turbomachine according to claim 1, wherein the variable outlet is defined by a plurality of chevrons, each of the plurality of chevrons being pivotally connected to the second end of the at least one nozzle.
 5. The turbomachine according to claim 4, further comprising: a chevron collar operatively connected to each of the plurality of chevrons.
 6. The turbomachine according to claim 5, wherein the chevron collar is shiftably mounted to the at least one nozzle.
 7. The turbomachine according to claim 4, further comprising: an actuator rod operatively connected to the chevron collar, the actuator rod being adapted to selectively shift the chevron collar between a first position wherein the variable outlet is configured at the first dimension and a second position, wherein the variable outlet is configured at the second dimension, the second dimension being distinct from the first dimension.
 8. An ejector for a turbomachine comprises: at least one nozzle having a first end portion that extends to a second end portion through a flow region, the second end portion including a variable outlet configured to control an airflow from a compressor.
 9. The ejector according to claim 8, wherein the at least one nozzle includes a first nozzle and a second nozzle, the second nozzle being slidingly disposed with the first nozzle.
 10. The ejector according to claim 9, wherein the first nozzle includes a first chevron portion that defines a first dimension for the variable outlet and the second nozzle includes a second chevron portion that defines a second dimension for the variable outlet, the second dimension being distinct from the first dimension, the second nozzle being shiftable between a first position, wherein airflow from the compressor passes through the variable outlet configured at the first dimension, to a second position, wherein the airflow from the compressor passes through the variable outlet configured at the second dimension.
 11. The ejector according to claim 8, wherein the variable outlet is defined by a plurality of chevrons, each of the plurality of chevrons being pivotally connected to the second end of the ejector.
 12. The ejector according to claim 11, further comprising: a chevron collar operatively connected to each of the plurality of chevrons.
 13. The ejector according to claim 12, wherein the chevron collar is shiftably mounted to the at least one motive nozzle.
 14. The ejector according to claim 12, further comprising: an actuator rod operatively connected to the chevron collar, the actuator rod being adapted to selectively shift the chevron collar between a first position wherein the variable orifice has a first dimension and a second position, wherein the variable orifice has a second dimension, the second dimension being distinct from the first dimension.
 15. The ejector according to claim 14, wherein the first dimension defines a first diameter and the second dimension defines a second diameter.
 16. A method of controlling an airflow through an ejector for a turbomachine, the method comprising: generating an airflow in a compressor portion of the turbomachine; guiding the airflow to an ejector; passing the airflow to a nozzle of the ejector; and passing the airflow through a variable outlet portion of the nozzle.
 17. The method of claim 16, wherein passing the airflow though the variable outlet comprises shifting a secondary nozzle portion, arranged within the nozzle from a first position, wherein the airflow passes though the variable outlet portion configured at a first dimension, and a second position wherein the variable outlet is configured at a second dimension, the second dimension being distinct from the first dimension.
 18. The method of claim 16, wherein passing the airflow though the variable outlet comprises pivoting a plurality of chevrons arranged on the nozzle from a first position, wherein the variable outlet portion is configured at a first dimension, to a second potion wherein the variable outlet portion is configured at a second dimension, the second dimension being distinct from the first dimension.
 19. The method of claim 16, further comprising: selectively shifting a chevron collar to pivot the plurality of chevrons.
 20. The method of claim 16, further comprising: passing the airflow at the desired pressure from the ejector into a turbine portion of the turbomachine. 